m5::stl::optional< T & > Class Template Reference

#include <optional.hpp>

Public Types
using	value_type = T &

Public Member Functions
template<class F >
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t< F, T & >	and_then (F &&f) &
template<class F >
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t< F, T & >	and_then (F &&f) &&
template<class F >
constexpr detail::invoke_result_t< F, const T & >	and_then (F &&f) const &
template<class F >
constexpr detail::invoke_result_t< F, const T & >	and_then (F &&f) const &&
template<class F >
TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval< optional & >(), std::declval< F && >()))	map (F &&f) &
	Carries out some operation on the stored object if there is one.
template<class F >
TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval< optional && >(), std::declval< F && >()))	map (F &&f) &&
template<class F >
constexpr decltype(detail::optional_map_impl(std::declval< const optional & >(), std::declval< F && >()))	map (F &&f) const &
template<class F >
constexpr decltype(detail::optional_map_impl(std::declval< const optional && >(), std::declval< F && >()))	map (F &&f) const &&
template<class F >
TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval< optional & >(), std::declval< F && >()))	transform (F &&f) &
	Carries out some operation on the stored object if there is one.
template<class F >
TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval< optional && >(), std::declval< F && >()))	transform (F &&f) &&
template<class F >
constexpr decltype(detail::optional_map_impl(std::declval< const optional & >(), std::declval< F && >()))	transform (F &&f) const &
template<class F >
constexpr decltype(detail::optional_map_impl(std::declval< const optional && >(), std::declval< F && >()))	transform (F &&f) const &&
template<class F , detail::enable_if_ret_void< F > * = nullptr>
optional< T > TL_OPTIONAL_11_CONSTEXPR	or_else (F &&f) &
	Calls f if the optional is empty.
template<class F , detail::disable_if_ret_void< F > * = nullptr>
optional< T > TL_OPTIONAL_11_CONSTEXPR	or_else (F &&f) &
template<class F , detail::enable_if_ret_void< F > * = nullptr>
optional< T >	or_else (F &&f) &&
template<class F , detail::disable_if_ret_void< F > * = nullptr>
optional< T > TL_OPTIONAL_11_CONSTEXPR	or_else (F &&f) &&
template<class F , detail::enable_if_ret_void< F > * = nullptr>
optional< T >	or_else (F &&f) const &
template<class F , detail::disable_if_ret_void< F > * = nullptr>
optional< T > TL_OPTIONAL_11_CONSTEXPR	or_else (F &&f) const &
template<class F , detail::enable_if_ret_void< F > * = nullptr>
optional< T >	or_else (F &&f) const &&
template<class F , detail::disable_if_ret_void< F > * = nullptr>
optional< T >	or_else (F &&f) const &&
template<class F , class U >
U	map_or (F &&f, U &&u) &
	Maps the stored value with f if there is one, otherwise returns u
template<class F , class U >
U	map_or (F &&f, U &&u) &&
template<class F , class U >
U	map_or (F &&f, U &&u) const &
template<class F , class U >
U	map_or (F &&f, U &&u) const &&
template<class F , class U >
detail::invoke_result_t< U >	map_or_else (F &&f, U &&u) &
template<class F , class U >
detail::invoke_result_t< U >	map_or_else (F &&f, U &&u) &&
template<class F , class U >
detail::invoke_result_t< U >	map_or_else (F &&f, U &&u) const &
template<class F , class U >
detail::invoke_result_t< U >	map_or_else (F &&f, U &&u) const &&
template<class U >
constexpr optional< typename std::decay< U >::type >	conjunction (U &&u) const
	Returns u if *this has a value, otherwise an empty optional.
TL_OPTIONAL_11_CONSTEXPR optional	disjunction (const optional &rhs) &
	Returns rhs if *this is empty, otherwise the current value.
constexpr optional	disjunction (const optional &rhs) const &
TL_OPTIONAL_11_CONSTEXPR optional	disjunction (const optional &rhs) &&
constexpr optional	disjunction (const optional &rhs) const &&
TL_OPTIONAL_11_CONSTEXPR optional	disjunction (optional &&rhs) &
constexpr optional	disjunction (optional &&rhs) const &
TL_OPTIONAL_11_CONSTEXPR optional	disjunction (optional &&rhs) &&
constexpr optional	disjunction (optional &&rhs) const &&
optional	take ()
	Takes the value out of the optional, leaving it empty.
constexpr	optional () noexcept
	Constructs an optional that does not contain a value.
constexpr	optional (nullopt_t) noexcept
TL_OPTIONAL_11_CONSTEXPR	optional (const optional &rhs) noexcept=default
TL_OPTIONAL_11_CONSTEXPR	optional (optional &&rhs)=default
template<class U = T, detail::enable_if_t<!detail::is_optional< detail::decay_t< U > >::value > * = nullptr>
constexpr	optional (U &&u) noexcept
	Constructs the stored value with u.
template<class U >
constexpr	optional (const optional< U > &rhs) noexcept
	~optional ()=default
	No-op.
optional &	operator= (nullopt_t) noexcept
optional &	operator= (const optional &rhs)=default
template<class U = T, detail::enable_if_t<!detail::is_optional< detail::decay_t< U > >::value > * = nullptr>
optional &	operator= (U &&u)
	Rebinds this optional to u.
template<class U >
optional &	operator= (const optional< U > &rhs) noexcept
template<class U = T, detail::enable_if_t<!detail::is_optional< detail::decay_t< U > >::value > * = nullptr>
optional &	emplace (U &&u) noexcept
	Rebinds this optional to u.
void	swap (optional &rhs) noexcept
constexpr const T *	operator-> () const noexcept
	Returns a pointer to the stored value.
TL_OPTIONAL_11_CONSTEXPR T *	operator-> () noexcept
TL_OPTIONAL_11_CONSTEXPR T &	operator* () noexcept
	Returns the stored value.
constexpr const T &	operator* () const noexcept
constexpr bool	has_value () const noexcept
constexpr	operator bool () const noexcept
TL_OPTIONAL_11_CONSTEXPR T &	value ()
	Returns the contained value if there is one, otherwise throws bad_optional_access.
TL_OPTIONAL_11_CONSTEXPR const T &	value () const
template<class U >
constexpr T	value_or (U &&u) const &noexcept
	Returns the stored value if there is one, otherwise returns u
template<class U >
TL_OPTIONAL_11_CONSTEXPR T	value_or (U &&u) &&noexcept
	\group value_or
void	reset () noexcept
	Destroys the stored value if one exists, making the optional empty.

Detailed Description

template<class T>
class m5::stl::optional< T & >

Specialization for when T is a reference. optional<T&> acts similarly to a T*, but provides more operations and shows intent more clearly.

Constructor & Destructor Documentation

optional() [1/2]

template<class T >

TL_OPTIONAL_11_CONSTEXPR m5::stl::optional< T & >::optional ( const optional< T & > & rhs )

defaultnoexcept

Copy constructor

If rhs contains a value, the stored value is direct-initialized with it. Otherwise, the constructed optional is empty.

optional() [2/2]

template<class T >

TL_OPTIONAL_11_CONSTEXPR m5::stl::optional< T & >::optional ( optional< T & > && rhs )

default

Move constructor

If rhs contains a value, the stored value is direct-initialized with it. Otherwise, the constructed optional is empty.

Member Function Documentation

and_then()

template<class T >

template<class F >

TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t< F, T & > m5::stl::optional< T & >::and_then ( F && f ) &

inline

Carries out some operation which returns an optional on the stored object if there is one.

map_or_else()

template<class T >

template<class F , class U >

detail::invoke_result_t< U > m5::stl::optional< T & >::map_or_else ( F && f, U && u ) &

inline

Maps the stored value with f if there is one, otherwise calls u and returns the result.

operator=() [1/3]

template<class T >

optional & m5::stl::optional< T & >::operator= ( const optional< T & > & rhs )

default

Copy assignment.

Rebinds this optional to the referee of rhs if there is one. Otherwise resets the stored value in *this.

operator=() [2/3]

template<class T >

template<class U >

optional & m5::stl::optional< T & >::operator= ( const optional< U > & rhs )

inlinenoexcept

Converting copy assignment operator.

Rebinds this optional to the referee of rhs if there is one. Otherwise resets the stored value in *this.

operator=() [3/3]

template<class T >

optional & m5::stl::optional< T & >::operator= ( nullopt_t )

inlinenoexcept

Assignment to empty.

Destroys the current value if there is one.

transform()

template<class T >

template<class F >

TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval< optional && >(), std::declval< F && >())) m5::stl::optional< T & >::transform ( F && f ) &&

inline

\group map \synopsis template <class F> auto transform(F &&f) &&;